import math

class Cycle(object):
    def __init__(self,radius):
        self.radius=radius

    def get_girth(self):
        girth = self.radius * 2 * math.pi
        print('周长='+str(girth))
        return girth

    def get_area(self):
        area = self.radius ** 2 * math.pi
        print('面积='+str(area))
        return area
while 1:
    r = int(input('请输入半径：'))
    if 1<= r <= 100:
        c = Cycle(r)
        c.get_area()
        c.get_girth()
        break
    else:
        print('请重新输入半径：')
